Segmented mirror

ABSTRACT

The invention concerns a method of making a segmented mirror, the mirror comprising, in combination 
     (a) a myriad of surfaces carried by a support, certain of said surfaces dimensionally offset from one another in a common direction generally parallel to the general direction of incident radiation to reflected, said surfaces being radiation reflecting sufaces each oriented in such a way that as a group they collectively reflect radiation essentially as they were a continuous reflecting surface, 
     (b) each of said surfaces having a periphery comprising an irregular or repeating series of line segments which are connected, curved or linear, the peripheries of said surfaces, when projected in said common offset direction onto a plane perpendicular thereto, contiguously conforming to one another, 
     said method including providing a die, used for casting the mirror segmented surface and constructing the die from a casting of a continuous surface of the desired shaped by cutting said casting, or a casting thereof, into small segments, and the segment cross sections being of any outline except circular, in order that the segments may be translated with respect to contiguous segments while maintaining integrity of the composite reflection of all the translated surfaces. 
     The invention also concerns a mirror having multiple interfitting segments which are wavy edged.

BACKGROUND OF THE INVENTION

This is a division, of application Ser. No. 708,527 filed Mar. 4, 1985,now U.S. Pat. No. 4,678,280, which is a continuation-in-part of Ser. No.578,688, filed Feb. 9, 1984, now U.S. Pat. No. 4,560,256, which is acontinuation of Ser. No. 385,544, filed June 7, 1982, now U.S. Pat. No.4,470,665 which is a continuation-in-part of Ser. No. 233,106, filedFeb. 10, 1981 (now U.S. Pat. No. 4,368,951), which is acontinuation-in-part of Ser. No. 109,970, filed Jan. 7, 1980 nowabandoned.

This invention relates generally to mirrors comprising a myriad ofreflecting surfaces so aligned with respect to each other as to produceone virtual image, which may be plain or focused. More particularly, itconcerns mirrors of the type wherein the surfaces are irregular inoutline to minimize or prevent glint patterns. Furthermore, it relatesto lenses comprising a myriad of lense surfaces so aligned with respectto each other as to produce a focused image.

This invention may be used in the construction of rear view mirrors (forautomobiles) which afford a 160° or 190° angle of rear and flank viewfrom a mirror bracket only somewhat wider than a conventional rear-viewmirror. This mirror will afford an undistorted image through the rearwindow, and smaller virtual images from the left and right flanks andsides of the vehicle. The wider 190° angle of rear view is achieved byusing two glass plates as mounts (instead of one), joined in the centerwith chevron-shaped horizontal cross section, and placed in one bracket.

Most existing mirrors are continuous reflecting surfaces which may betwo-dimensional planar surfaces or three-dimensional curved surfaces(convex, concave or other). Conventional three dimensional shapedmirrors are bulkier than planar mirrors by virtue of the additionalmaterial needed to provide the third-dimension of the mirror surface.Commercially produced three-dimensional mirrors often have relativelylarge aberrations with attendant distortion of the images reflectedtherefrom. Reducing such distortions would significantly increase thecost of such mirrors.

In the past, mirrors have been proposed wherein multiple reflectingsurfaces, offset from one another, have regular form, as in U.S. Pat.No. 3,739,455 to Alvarez. Due to such repetition of regular outlines ofthe reflecting surfaces, linear glint patterns may be discerned by theviewer. As a result, that type mirror is not well suited to the specialmirror shapes, and uses disclosed herein, as for example rear viewmirrors for vehicles enabling panoramic viewing of one or both rearflanks of the vehicle as well as toward the rear thereof, the otherdevices.

SUMMARY OF THE INVENTION

It is a major object of the invention to provide a mirror construction,and a method of making same, the mirror being especially suited for rearview use in a vehicle, the basic construction comprising:

(a) a support, and

(b) a myriad of irregularly outlined, contiguous mirror surfaces carriedby the support, certain of such surfaces dimensionally offset from oneanother, in a common direction which may be parallel or sub-parallel tothe general direction of incident radiation to be reflected, so orientedwith respect to one another such taht the collective reflected imagefrom all mirror facets is essentially equivalent to the reflection froma continuous mirror surface

The myriad of contiguous mirror surfaces may be on the side of thesupport on which the radiation first impinges, or, if the support istransparent, such as a piece of glass, the metalized surfaces may be onthe reverse side of the glass, so that incident light first penetratesthe glass before being reflected, as is the case in most conventionalmirrors.

It is another object of the invention to provide a mirror of this typecontaining two or more groups of contiguous reflecting surfaces withinthe outline of one mirror frame. Within this frame each group ofradiation reflecting surfaces may face directionally differently. Thus,an observer can see two or more views by consulting one mirror frame.The groups of surfaces may occupy adjacent areas, or they may beinterspersed as will be seen, and a rear-view mirror may incorporatesame.

It is a further object of this invention to provide a design for massproducing mirrors, which, if fashioned or manufactured using existingtechniques would be impractical or too costly. It is also an object ofthis invention to provide a process for commercial manufacture of suchmirrors.

Another object of this invention is to enable the shape and/ororientation of the rigid unit supporting and/or containing the myriad ofmirrored surfaces to be other than perpendicular to the mirroredsurfaces. For example, the generalized shape of the surface comprisingthe myriad of reflecting planar facets may be three dimensional, whereasif the perpendiculars to each facet are all parallel, the gross effectof reflections from the facets taken together is essentially the same asthe reflection from a planar mirror, providing the angle of incidence iswithin a few degrees (of angle) of being parallel to the perpendicularsto each planar facet. (See FIG. 18).

An additional object of the invention is to enable the construction of apartially transparent mirror, combining mirror segments from one or moremirror surfaces with a set of transparent, non-silvered segments whichallow an effective view through the "mirror" area. If a set of parallelnon-silvered, flat surfaces are interspersed with a set (or sets) ofsilvered or reflecting surfaces, these transparent areas will allow afiltered view through the mirror area if the material of the rigidmirror is clear, such as glass, and if the viewer is on the dark side ofthe mirror.

Another object of the invention is to enable the combination within onemirror frame of an area comprising a conventional flat mirror with oneor more areas of segmented mirrors within one flat structurally rigidstable support. (See FIGS. 12 and 13).

Another object of the invention is to combine two or more flat stablesupports, each containing flat and/or segmented mirrors, into onestructurally rigid unit within one frame, or bracket (see FIG. 16b).

Another object of the invention is to diminish glint from the edges ofcontiguous mirror segments by metalizing only the surfaces of thesegments, and not their edges. Furthermore, the edges of the mirrorsegments may be treated to minimize glint by reducing the reflectance ofthe surface immediately adjacent to its edge, and of thenearly-perpendicular area of offset between contiguous mirror segments.

Another objective of the invention is to be able to adjust thereflectivity of a segmented vehicular rear view mirror so as to make theimage less intense for night viewing. This may be accomplished inseveral ways: by mechanically introducing a filter between the driverand the glass support carrying the mirror surfaces; by mechanicallyseparating the metalizing layer from the reflecting surfaces, therebyreducing the reflection coefficient of the mirror; or by mechanicallyadjusting the attitude of the glass support frame at night such that theflat front surface acts as a conventional flat mirror with relativelypoor reflectance.

Another objective of the invention it to utilize a method of manufactureof the master die for casting the plastic strip containing the offsetsegments of mirror, which insures very accurate orientation of themirror segments, such that the reflected view appears continuous to aviewer despite the fact that the mirror is segmented. This accurateorientation of mirror segments is achieved by maintaining only onecutting direction with respect to the master mold during segmentationthereof. Each segment cut from the master mold, when moved to conform tothe desired surface shape (usually flat), is constrained by the sides ofthe adjacent segments to move without rotation in the same direction asthe cutting direction.

Yet another object is to provide a method of guiding the irregularlyoutlined surfaces of a mole during their translation so as to preventlateral displacement of the mold surfaces, this technique being employedto maintain original orientation of each segment of the cast surface ofthe mirror. Also, image overlapping around the peripheries of adjacentindividual surfaces is prevented.

Still another object of the invention is to provide a mirror which hasmultiple segments which interfit at wavy edge location.

These and other objects and advantages of the invention, as well as thedetails of illustrative embodiments, will be more fully understood fromthe following description and drawings, in which:

DRAWING DESCRIPTION

FIGS. 1 through 9 show the sequence of steps for making a segmentedmirror, and are separately described as follows:

FIG. 1 is a vertical section through a flat-lying convex glass mirror;

FIG. 2 is a vertical section through a plastic negative casting on theFIG. 1 mold;

FIG. 3 is a vertical section showing laser beam cutting of the negativecasting into segments, the source of the laser beam perpendicular to aflat plate;

FIG. 4 is a section showing translation of the FIG. 3 segments tocontact a flat glass surface;

FIG. 5 is a section through a die that includes the FIG. 4 segments(immobilized) opposite a flat surface;

FIG. 6 is a positive casting from the FIG. 5 die;

FIG. 7 is a section through a negative die, constructed by using apositive casting from the FIG. 6 die;

FIG. 8 shows the transparent negative plastic casting resulting from thedie in FIG. 7;

FIG. 9 shows the casting of FIG. 8 transparently bonded to a transparentglass plate, with metalized surfaces; i.e., a complete segmented mirrorwhich reflects similarly to a convex mirror. (Actually the angle betweenincident and reflected light is somewhat larger in FIG. 9 than in FIG. 1because of the refraction at the front surfaces of the glass support.

In FIGS. 10, 11, 12 and 13 each diagram of the plan view of segments ofcastings is the same, because the same pattern of cuts is used each timein the segmentation process. This makes possible the substitution ofsegments to create one collage of two or more groups of segments. Thecollage of segments is then used as in FIG. 4.

FIG. 10 is a close-up plan view of segments of casting (perpendicular toC-axis);

FIG. 10a is a close-up cross section of displaced facets of segments ofnegative casting (c.f. FIG. 4);

FIG. 11 is a close-up plan view of segments of castings from two groupsof reflection surfaces;

FIG. 11a is a close-up cross section of the facets of segments ofcastings. Slopes to the left are the X group, and to the right are the Ygroups;

FIG. 12 is a close-up plan view of the facets of segments of castings ofR and S groups; S group is cast from a flat plate;

FIG. 12a is a close-up cross section of the facets of segments ofcastings. The R group on the left is in juxtaposition with the S groupon the right;

FIG. 13 is a close-up plan view of facets of segments of castings on theleft in juxtaposition with a casting from a flat plate, trimmed to fit;

FIG. 13a is a close-up of cross section of the facets of the segments ofcastings on the left, and a cross section of a casting from a flat plateon the right;

FIG. 14 shows a mixed junction between two groups of segments ofcastings;

FIG. 15a shows one configuration of a segmented rear view mirror, andFIG. 15b shows in plan the resulting 160° azimuth of rear and flankviews;

FIG. 16a shows a driver's view of a mirror comprising two supportingglass plates, rigidly connected;

FIG. 16b is a horizontal cross section of the mirror in FIG. 16a.

FIG. 16c shows in plan the 190° azimuth of rear and side views affordedby using the mirror pictured in FIGS. 16a and 16b;

FIG. 17a is an elevation showing the advantage of tilting theorientation of the support glass, such that the "ghost" reflection fromthe front of the support glass is from a poorly illuminated area, suchas the ceiling of the driver's cab, thereby making it virtuallyinvisible to the driver;

FIG. 17b is a fragmentary section through the FIG. 17a mirror;

FIG. 18 shows a segmented mirror on a three dimensional support, whichacts as a flat mirror, and shows the versitility of this inventionwhereby the shape of the support is independent of the shape of themaster mirror from which the segments were derived;

FIG. 19 is a plan view diagram of a conventional rear view from amirror;

FIG. 20 shows a schematic view of a camera incorporating the invention;

FIGS. 21-24 are perspective showings of steps to insure accuratedisplacement of irregularly outlined mold surfaces during theirlongitudinal translation into positions enabling casting of a mirrormedia; and

FIG. 25 is a side elevation showing details of guiding and peripheralconstriction of irregularly outlined mold surfaces; and

FIG. 26 is a plan view of wavy edged mirror segments.

DETAILED DESCRIPTION

Construction of such segmented mirror surfaces is best achieved byforming them from a plastic material, utilizing a die. The plasticmaterial may provide the necessary rigidity, or it may be cast into athin layer (flat on one side and the segmented surfaces on the other).The flat side of the thin layer is then adhered to a dimensionallystable flat material such as glass. The metalized reflecting surface maybe either the air-reflector interface on which the indicent ligh firstimpinges, or, if all materials are sufficiently transparent, theimpinging light may travel through these materials and be reflected by amirroring material on the "back" side. The latter generally would bepreferable to protect the metalized surface, and to facilitate cleaningof the exposed surface.

In order to construct a die as seen in FIG. 17, a model as at 10 in FIG.1 with a continuous surface 11 is constructed in the shaped of thedesired reflector. Glass, plastic or some other suitable material may beused for this model, from which a negative copy 12 is molded as in FIG.2 in some suitable material, such as an opaque thermoplastic. Thisnegative casting 12 is then cut into segments 13 in such a manner thatthe orientation of the cutting direction (C-axis) is constant and alwaysthe same with repsect ot the negative casting. This common direction, asfor example vertical, should be approximately the average direction ofperpendiculars to the resulting mirror segments. One convenient mannerof cutting the casting is with a laser beam 14, the laser 14a held in ajig which keeps the beam perpendicular to flat surface 15. See FIG. 3.

After the negative casting is cut into segments, for which perpendicularcross sections are preferably irregular in outline, the segments 13 aretranslated short distances relative to one another, in the same C-axisdirection which is common to all the cut surfaces. The distance oftranslation would be such that the surfaces of individual segments 13 ofthe negative casting each touch the surface to which it is desired thatthey conform, such as the flat surface 15.

It is essential that the segments of the casting are not rotated aroundany axis. Their only movement is translation in the direction of theC-axis, and each segment must retain its same contiguous neighborsegments before and after translation. As long as any segment cut fromthe negative casting is not circular or ring-shaped in cross sectionperpendicular to the C-axis, and as long as the segments are kept incontact, translation without rotation of the segments is easily andaccurately accomplished because the elongate segments have only onedegree of freedom of movement with respect to one another, i.e.translation along the C-axis.

The segments are then immobilized with respect to one another, as forexample by bonding the segments 13 with backing material 18, at bondlocations 16, and the resulting stabilized mosaic of displaced segmentsof the original reflecting surface may be used to make a positive dieFiG. 5 (and subsequently a negative die FIG. 7) for manufacturingreplicas of that mosaic surface. Only the displaced facets of theoriginal reflecting surface are to be made reflective (i.e. metalized)on the replica mosaic surface.

The replicas of the small portions of the cut surface exposed in themosaic (nearly at right angles to the reflecting surfaces) may be left"optically rough" and may not be metalized.

A further reduction in glint may be effected by not metalizing theperiphery of each facet, thereby reducing distracting optical effectscaused by the interaction of adjoining facets and the reflection fromthe cut faces separating them, and also reducing effects of anyimperfections in the castings of the reflecting surfaces, whichimperfections would tend to be concentrated in these peripheral areas.

FIGS. 5 and 7 show dies formed from the FIGS. 5 and 6 structures, andinclude side supports 19 and a flat cover plate 17. Casting spaces 20and 22 are thereby formed between plates 17 and surfaces 13c and 21c ofmosaics 13 and 21, respectively. FIG. 6 shows a casting 21 made byintroduction of plastic into space 20 of FIG. 5, and havingcorresponding mosaic surface 21c which is a negative image of thesurface 13c formed in FIG. 4. The casting 23 may for example consist oftransparent plastic material, such as polystyrene or other material.Referring to FIG. 9, the casting may be supported on a glass backer 25,and the mosaic surface will be selectively metallized at 26, i.e. onlysurfaces (corresponding ot original segments) of a first group orselected groups will be metalized. The outlines of the segments shouldbe irregular and without parallel straight line segments to obviate theformation of discernible glint patterns. See FIG. 14 in this regard.

Vehicle Mirror for Rear and Side Views

Conventional rear view flat mirrors afford the driver of a motor vehiclea reflected view of a limited azimuth, restricted by the dimensions ofthe mirror, of the rear window, and distance of the mirror from theviewer. Such mirrors leave "blind spots" on both rear flanks, which thedriver cannot see. This is the cause of traffic accidents when thedriver does not properly monitor and take into account the presence ofnearby vehicles. Convex mirrors are sometimes used to provide a widerangle of reflected rear view vision, but these mirrors produce smallvirtual images, and the resolution of the reflected view out the rearwindow is much inferior to that of the conventional flat mirror.Furthermore, the driver has difficulty in judging distances to objectsin the small virtual image. Therefore, drivers sometimes use a convexmirror or mirrors for flank view(s) as well as a conventional flatmirror, thus causing the driver to consult two or more mirror bracketsto appraise what is happening near the rear and flanks of his vehicle.

By using the principles of the segmented mirror, as described herein, anew type of mirror is provided which will afford an undistorted "flat"reflected image through the rear window as well as small-scale,"condensed" virtual images of both rear flanks of the vehicle, allwithin one rigid structural unit not much larger than that used for aconventional rear view mirror.

One problem for a driver attempting to alternate his attention betweentwo or more mirrors (a flat mirror and convex mirror(s)) is that he musttake the time and conscious effort to redirect the azimuth of his visualattention and he must change the distance at which his eyes arefocussed. The focus of his eyes is distant for the flat mirror and closerange for the convex mirror(s). As a person becomes older, this becomesmore of a problem for many drivers because visual redirection andrefocussing takes more time and increased effort. By having all themirror surfaces within one frame, as enabled by the invention, thedriver may glance to the rear view without having to changesubstantially the distance of focus of his eyes from that which he usesfor looking forward through the windshield at the road ahead, while atthe same time his peripheral vision can quickly evaluate whether avehicle is threateningly near either flank of his vehicle. This quickevaluation, without having to refocus to the closer virtual imagesflanking the undistorted view out the rear window, is possible becausethe flanking image of a nearby vehicle moving in the same direction willappear as nearly "stationary" whereas the more-distant middleground willappear to be "flying-by" because of the relatively rapid angularvelocity of stationary objects, when viewed by the driver of a movingvehicle via the mirror. This "stationary" look vs. a "flying-by"impression is readily perceived by the peripheral vision and thereforethe presence of a nearby vehicle off the flank of the driver's vehicleis easily noted by the driver.

The stereoscopic image one observes with both eyes in a conventionalrear view mirror is augmented by monoscopic continuations of the imageon either side. The left eye extends the reflected image of distantobjects monoscopically to the right by an amount measured horizontallyin the plane of the mirror almost as great as the distance between thepupils of the eyes of the observer. Conversely, the same effect occurswith the right eye. The mind combines the central stereoscopic imagewith the two adjoining monoscopic images into the mental image,comprising the rear view. The observer usually does not realize wherethe stereo portion of the image terminates, i.e. it all registers as oneimage to the observer. See FIG. 19 in this regard.

Optimum Design--Rear View Mirror

One optimum design of segmented rear view mirror, to be located insidethe vehicle near the center of the windshield will include a centralarea derived from a planar surface, and two areas (left and right) forviewing the left and right rear flank views. The width of the entirecomposite mirror is typically about 25 centimeters, and the height about5.5 centimeters, similar to the dimensions of many conventional planarrear view mirrors. The rear flank views should be derived according tothe methods of this invention from areas of master mirrors shapedsomewhat like sections from vertically standing barrels. The "barrelshape" should be sufficiently convex along a vertical plane such thatthe reflected view out the side windows will subtend the entire heightof those windows. The cylindrical curvature should be such that thewidth of each mirror area is about 6 or 8 centimeters for a horizontalazimuth of vision of 60 to 70 degrees.

In order to minimize the width of this mirror, to facilitate thedriver's peripheral awareness of the flank views, and to provide amaximum angle of view for each of the three views (rear and both flanks)visible from the composite mirror, mixed junctions as previouslydescribed (see FIG. 14) perhaps about 1.5 cm. wide, join the centralarea 40 with the flanking areas 42 and 43 of this rear view mirror. Themixed junctions 41 may be slanted, as shown in FIG. 15a, to enhance thedriver's perception of the last glimpse of a passing vehicle, visiblethrough the lower corner of the rear window in many automobiles.

Another optimum design of a rear view mirror made according to thisinvention affords an azimuth of view of 190°, more or less. This isaccomplished by joining two glass backers, such that they form achevron-shape in horizontal cross section, with the peak 150 pointedtoward the driver, as can be seen in FIGS. 16a, 16b and 16c. When therear view sections 140 are accurately positioned and immobilized withrespect to one another (FIG. 16a), then the user's mind will perceive anunbroken stereoscopic rear view, and the line 150 marking the joining ofthe two backers will be virtually unnoticed by the driver. The mixedjunction 141 correspond to those at 41 in FIG. 15a, and flank sections142 and 143 correspond to those at 42 and 43 in FIG. 15a.

In the case of a mirror with one glass backer, one would expect that themirror sector for the view of the left flank should subtend a flankingview somewhat wider than for the right flank, as necessitated by thegeometry of the orientation of a conventional rear view mirror to thedriver. However, using the principals of mirror-segmentation embodied inthis invention, the frame of the composite mirror may be oriented toextend the angle of reflected vision more to the right flank (whilecommensurately reducing the angle of left flank vision). This has theadvantage of minimizing any gap in vision between the junction of theforward peripheral vision and the reflected vision of each flank. SeeFIG. 15b in this regard.

In some cases and as referred to above, it may prove advantageous tomake these junctures mixed rather than abrupt. Mixed junctures in theresultant composite mirror are made by mixing reflecting facets fromadjoining families of mirror sectors such that within the zone of mixedjuncture both adjoining mirror families will be represented. Theconcentration or a real density of the number of rear view reflectingsectors of one family may grade from 100% at the edge of that mirrorarea to 0% at the other edge of the mixed juncture. Concurrently thepercentage of sectors resulting from the other "master" mirror wouldincrease from 0 to 100% across the zone of mixed juncture. Or thepercentage or representatives of each group throughout the zone of mixedjuncture may be constant. See in this regard FIG. 14 with reflectingareas of sets P and Q corresponding to mirror areas 40 and 42, or 40 and43 in FIG. 15a, and the mixed juncture zone (P and Q) corresponding tomirror area 41.

The mixing of groups of facets within the zone of mixed juncture isaccomplished by substitution of appropriate coincident segments of theidentically shaped patterns of negative castings of adjoining groups ofsegments (with common C-axis for all segments). From the resultantcoilage a single die is made for the entire composite mirror within thebracket.

The advantage of a mixed juncture (as in FIG. 14) in this case is thatin the zone of juncture within the area of the composite mirror, imagesfrom both the centrally-located flat mirror as well as from the convexmirrors on the left and right sides will be perceived by the driver. Theimage perceived by the driver of an overtaking automobile will be a"nearly stationary" shape blending from a view seen towards the edge ofthe rear window to a smaller "nearly stationary" view out the flankwindow (surrounded by the blurred rush of the background). The mixedjuncture will assist the driver's mind to integrate the two views andrecognize the continuity of movement of the overtaking auto as it movesfrom behind to alongside the flank of the driver's vehicle, until thedriver's peripheral vision directly "picks up" the overtaking auto bydirect view out the side window. Using mixed junctures enables thedesign of a composite mirror which will take up less horizontal width,thereby affording a more unrestricted view by the driver forwardsthrough the windshield, and enabling easier mental assimilation andrecognition of continuity of movement of nearby traffic off both flanksof the vehicle. This is possible because the concurrent views observedby the driver from both flanks are closer together and therefor easierfor the mind to perceive by direct and peripheral observation withminimum shifting or refocussing of the driver's eyes.

However, for the purpose of this invention, the juncture zones betweenthe undistorted central portion of the composite mirror and theoriginally convex flank mirrors may be either smoothly transitional(continuous curvature of one "master" mirror surface, flat in the centerand convexly shaped at both ends), abrupt (sudden change from one mastermirror surface to another), mixed (as described above), or a combinationof these. Each flanking mirror may be junctured so as to minimize theviews of the corner posts and driver, in which case the composite mirrormight have several n families of reflecting facets with n-1 juncturezones.

CONSTRUCTION OF THE MIRROR

The first step in constructing the mirror, an example of which is seenin FIG. 15a is to determine the angular subtendance of rear and sidewindows from the vantage point of the intended location of the mirrorinside the vehicle near the upper central area of the windshield. Thecentral portion 40 of the subject mirror is sized and oriented to afforda complete undistorted view through the rear window. For the left andright flanks, suitable convex mirrors 42 and 43 are designed. Thesedesigns should accommodate the transition from reflected views throughrear and flanking windows, so the driver easily may "follow" themovement of nearby vehicles traveling in the driver's direction oftraffic as they pass from view through rear window to rear flankingwindows (or vice versa). The curvatures of the side mirrors 42 and 43may be designed to make the transition gradual from the undistortedcentral reflecting area 40 to the convex flank reflectors. Each sidemirror may be designed with any convex curvature, including spherical orcylindrical curvature, but more likely a complex convex curvaturefashioned to increase the usefullness of the resultant view out theflanking windows.

In order to minimize the width of the "bracket" 44 of the three or moregroups of mirror facets, so as to minimize obstruction to the driver'sview forward and to facilitate peripheral perception by the driver, thecomposite mirror system is designed so that the advantages of each ofthe views are optimized with minimum interference and maximumaccommodation to each other. The optimum relative locations of each ofthe original overlapphing "master" mirrors are determined. Castings aremade of each mirror and the castins segmented, in accordance with theprincipals of this invention with a constant C-axis direction ofsegmentation common to all "master" mirrors. This C-axis direction mustbe a constant direction parallel to the general direction of incidentradiation to be reflected. The pattern of segmentation intended for thefinished segmented mirror must be used for segmenting each of theadjoining master castings. Each such adjoining casting of a mastermirror must be properly located and oriented with respect to the otherssuch that in the zone of overlap between the sets of segments fromadjoining master castings shares identical segments, enabling selectionof a boundary, between the two sets of segments with a snug fit betweenthe adjoining sets of segments.

A jig, affixed on the interior of the cab of the vehicle near theintended location of the composite mirror, may be used to capture theoptimum location and relative orientation of each of the (overlapping)"master" mirrors with respect to each other, as well as to the directionof the optimum C-axis, the common segmentation direction for castingfrom all three "master" mirrors. The settings for the holder of each"master" mirror are then used to orient and locate the casting of each"master" mirror with respect to the C-axis direction of segmentation.The pattern of movement to which the cutter is confined, i.e. onetemplet or pattern located perpendicular to the C-axis, covers theentire field of the intended composite mirror, such that the overlappingportions of adjacent areas are segmented in identical patterns. Thepattern of segmentation must be common to portions of overlap ofadjoining "master" mirrors, so that the optimum locations and natures ofthese junctures may be chosen.

Second Example--Camera Utilizing Segmented Mirrors

Another utilization of cast segmented-mirrors constructed in the samemanner as in the previous example is in a camera where the image on thefilm is created by light reflected from a segmented mirror. In FIG. 20,the segmented mirror 25' is contained with camera housing 26' to receivelight via glass plate 29 and over a field of view designated at 27. Apeep hole for sighting appears at 28. Mirror 39 reflects light from themirror 25' to film 31, via shutter and diaphragm indicated at 32. In onecamera, more than one segmented mirror, each with differing focallengths, may be used by providing a system for exchanging mirrors.

To minimize aberrations, light is preferably reflected directly frommetallized concave segmented mirror sectors rather than travelingthrough the casting and support plate first. In order to keep the mirrorsurface clean, the internal portion of the camera is sealed and lightwill be admitted through the protective glass plate. Light reflectedfrom the main segmented mirror is reflected by a flat metallized mirrorsurface at 29 set at an angle to the axis of the main mirror and locatednear the focal point of the main mirror, such that the image will befocussed on a conveniently oriented focal plane outside the path of theincoming light.

Several adjacent sectors within the area of the main mirror 25' may bedesigned so as to act as the transparent "peep-hole" suitable for thephotographer to target and/or focus the camera. This is achieved bycutting the casting of the special mirror, with the identical pattern ofsectors, to that used for cutting a casting of a flat plate, and bysubstituting a bundle of segements from the flat casting for anidentical bundle of segments from the casting of the mirror. Thereflecting side of castings from the resulting die are metallized exceptfor the area of flat sectors, which transmit light without any focussingeffect to the photographer's eye in back of this "peep-hole" in themirror.

To construct a lens, using the principals of this invention, a specialmaster lens is used, such as in FIG. 1; however, the design of themaster lens must be such that the negative casting 23 in FIG. 8 has onefocal point for all lens segments. The negative casting 23 is thenadhered to the top surface of a flat glass backer, and/or the positivecasting 21 of FIG. 6 is adhered to the bottom surface of a flat glassbacker to form the lens.

In the above description, a casting made from a flat or curvedmirror-smooth surface is segmented to form a master die or mold. Thesegmentation is typically accomplished by cutting the casting intopieces using a laser beam or other device, and then the segments aremoved parallel to the unique direction of cutting (C-axis), so that thesegments all impinge on a surface of the desired shape, usually a flatplane. This process typically involves crowding the segments togetheruntil their parallel cut surfaces touch. Such touching should insurethat the original orientation of a sector of the mirror surface ismaintained in the orientation of the corresponding segment. However, ifthe two sides on the cut are not exactly parallel, when they are pressedtogether the segments of the casting will not perfectly retain theiroriginal relative orientation, and thus each segment of the cast surfaceof the mirror will not retain its original orientation vis a vis theother segments. In addition, in the process of being crowded together,adjacent segments (cut from convex surfaces) suffer a relative lateraldisplacement equal to the width of the cut. The resulting mosaic ofsurfaces, if metalized, would yield a reflection with very minoroverlaps in the image around the periphery of each individual surface.

These aforementioned problems may be eliminated in the manner now to bedescribed. Typically, the method involves blocking lateral displacementof the segments while they are translated longitudinally. For example,three or four cylindrical holes or guide openings such as at 201-206 inFIGS. 21 and 22 are drilled (parallel to the C-axis) at locations spacedaround the intended peripheries of the individual surfaces or segmentsbefore segmenting the original casting. See cuts 207-212. After thesegmentation is complete, a straight rod or hollow tube of circularcross section equal in diameter to that of the hole is inserted betweenthe two remaining walls of each hole. See for example rods 213-215 inFIG. 23. After segmentation by cutting parallel to the C-axis, thesegments of the original casting are then translated parallel to theC-axis so that each segment impinges on the surface of desired shape(usually a flat plane as at 216 in FIG. 24). The movement of eachsegment is confined to the C-axis direction, and there is no "crowdingtogether" of the segments, because they are held apart by the rods ortubes of diameter the same as the diameter of openings 201-206. The rodsor tubes should not protrude above the reflecting surface of the mosaicof segments, and as further precaution against any optical interferencewith the segmented mirror, the ends of the rods or tubes adjacent theirregularly outlined under-surfaces of the segment (see segments 220-225in FIG. 23) may either be cut on an angle large enought to insureinternal reflection from these surfaces in any mirror constructed usingthe principals of this invention, or the ends of the rofds or tubes maybe made optically rough. See rod lower end 214a in FIG. 25, for example.

The described holes are also useful in ensuring accurate setting of theintended angular relationship between the C-axis and the orientation ofthe surface of desired shape (usually a flat plane), against which eachsegment of the original casting is made to impinge. This is accomplishedby drilling identically located holes in a second rigid block 230 ofmaterial into which a number of rigid guide rods are inserted. See guiderods 231-233 in holes 201, 234, and 235 in mold 236, and extending intoholes 201a, 234a and 235a in block 230 in FIG. 24. The lengths of theguide rods extending from the surface of the second sheet or block 230is such that their ends form a plane 216 of the desired shape andorientation against which the segments are to impinge. First the guiderods 231-233 are inserted into the corresponding holes while rods ortubes 213-215 etc. are inserted in the remaining holes. Then the mosaicof casting-segments are adjusted i.e. translated to the desired plane216. Thereafter a peripheral constriction typically is applied to themosaic, immobilizing same, and finally an adhesive material whichbecomes hard is implaced between the mosaic and the rigid block 230.This forms a rigid block suitable to be the surface in a die to be usedin accordance with the principals of this invention. See the lateralconstriction means 241 and 242 in FIG. 25, the adhesive material 243, inFIG. 25, for example.

From the foregoing, the steps of the method of FIGS. 21-25 include:

(a) cutting irregularly outlined segments of a mold, the segmentsdefining irregularly outline surfaces suitable for a mirror mold,

(b) and longitudinally translating said segments in said commonlongitudinal direction while blocking lateral displacement of saidsegments.

In this regard, the step of blocking lateral displacement of the moldsegments includes forming longitudinal guide openings in said mold,prior to said cutting step, to intersect the intended peripheries of theirregularly outlined segments of the mold. Further, the blocking stepmay include inserting longitudinally extending guides into said guideopenings, to guide said longitudinal translation of the mold segments.Certain guides (as at 231-233) adjusted to contact a desired surface (asat 216) may be located to help fix the terminal position of translationof each segment during its translation; and such guides may includeproviding a block as at 230 with locating openings therein to receiveextensions of the guides.

Referring to FIG. 26, the illustrated mirror 400, shown in a viewgenerally like FIG. 10, has multiple segments 401, of polygonal (as forexample generally triangular) outline. The segments interfit at theiredges 402, which are wavy. Such edges of peripheries may advantageouslyhave approximately sinusoidal configuration, along their lengths,whereby the advantages of irregularity are achieved yet all the segmentsmay be identical or near identical in overall shape and size. Thetriangular shapes shown have equal length sides (as in an equilateraltriangle); however the triangles may be isosceles or scalar, so long astheir edges are wavy. A linear succession of interfitting segments isdesignated at "1, 2, 3, - - - 12." Guide openings are indicated at 403for one row of segments.

I claim:
 1. A mirror comprising a plurality of interfitting mirrorsegments, the segments having multiple edges which have approximatelysinusoidal configuration.
 2. A mirror comprising a plurality ofinterfitting mirror segments, the segments having multiple edges whichare wavy, the mirror mounted in or on a vehicle to define a rear or sideview mirror to the eye of the driver.